Set Analysis Sum({1<DIM>}KPI) not equal Sum({$<DIM=P()>}KPI) if nothing selected

[Anonymous]

Dear Community,

as i am understanding set analysis correctly

Sum({1<DIM>}KPI) should give the same result (if nothing is selected of DIM) like Sum({$<DIM=P()>}KPI)

But Sum({$<DIM=P()>}KPI) shows not the same number, its only nearly (95%) the same as  Sum({1<DIM>}KPI) !

Why is this happening, where is my mistake?

[Anonymous]

I solved this by using:

if(getselectedcount(DIM)>=1,

     Sum({1<DIM=p(DIM)>}KPI),

     Sum({1<DIM=p(DIM)>+1-<DIM=e(DIM)>}KPI)

)